Catalytic promotion of the adsorption of vanadium on an anionic exchange resin



Aug. 26, 1958 VANADIUM ON AN Filed Oct 7, 1952 Aoidi'c Ph osphaticSolution Vanadium (tetrova/ent) ANIONIC EXCHANGE RESIN 3 Sheets-Sheet 1Acidic Phosphate Solution Van adium (pentavalent) (U*, U" and/or othermaterial) (U+ and/or other material) (Cations) (Cations) FLUOR/DIOABSORPTION PROMOTE)? OX/DIZING (Fluoride salt) AGE N T (electrolytic)(Mn 0 H"; P0 v+5, uFS) (other material) (Cations) i (other material)(Cations) ELUTRIANT 1 Na s0 EFFLUENT EFFLL/ENT (P0 etc.)

ELUTRIANT (W (H20), (S0204) v ELUTION FLUORIDATION (of Solution) (SilicaFluoride) (other Fluoridic material) FLUORIDATION (of Resin Column)ABSORPTION (Anionic Exchange Resin) (Chloride or Sulfate form) {RssiivFLUORIDE (CIor $0 form) (other Cationic material), (Cations) ADSORPTIONEFF L UENT H", P04=, (Fluoride) PHOSPHATE REMOVAL RESIN ADSORBATE r ii,u+6

lu) Fluoride P04 (other Anionic material) RES/N ADSORBA TE ELUTR/ANT ($0aq.) (H2504 50 (F0 $0 aq.)

SIMULTANEOUS SELECTIVE REDUCTION 8i ELUTION OF V ELUTR/ANT (we 1a),ELUTRIANT 8 Dilute Acid EFFLUENT (e.g. H6! H2 so RES/N ADSORBATERecovery:

(Dilute chloride) +s (some P047304) U ELUTION (Amine Hydrochloride) EF FLUENT EFFLUENT U+6 ELUTI o N RES/N nui s oivsArE u fi g ii RES/NADSORBATE} 2 2 V+5 REDUCING AGENT 'jZgfl (S02 gas) (50 aq.) (F8304)REDUCTION SIMULTANEOUS REDUCTION {H2504+3O2-) RESM, a ELUTION OFVANADIUM (Fe $0 ea) H20 4 INVENTORS (S02 aqui RICHARD H. BA/LES ELUT ONI BY DAV/D A. ELLIS 4m EFFLUENT m4 to VRecovery F I G. 1

. ATTORNEY Filed Oct. 7, 1952 GRAMS VANADIUM/LITER SOLUTION H. BAILES ETAL ION OF THE ADSORPTION OF ANIONIC EXCHANGE RESIN 5 Sheets-Sheet 2Anionic Exchange Treated Resin Solution 0 CI l A Cl 3 l I I I I I0 20 3O4O 5O 60 mg VANADIUM/ml RESIN INVENTORS RICHARD H. BA/LES B DAVID A.ELL/S ATTORNEY Aug. 26, 1958 R. H. BAILES ET AL 2,849,279

CATALYTIC PROMOTION OF THE ABSORPTION OF VANADIUM ON AN ANIONIC EXCHANGERESIN Filed Oct. 7, 1952 3 Sheets-Sheet 5 CONCENTRATION OF V SolutionPhase O IO 20 3O 4O 50 (g/l) FIG. 3-

INVENTORS RICHARD H. BAILES LLI By DAVID A E S flaw/4. Wow/m ATTORNEYfluoride ion added to United States Patent 2,849,279 aRa tentedVAug.-26, n1.958

v Richard:H.'LBailes,kWalnut Greek, and David A.. Ellis,

" .C oncor d,-, Califi, assignors, by 1 mesne. assignments, to theUnited States of America as representedq-hy the United States AtomicEnergy Commission Application October- 7, 195. S,er,ial--No.;3.1 ,558 8Claims. (Cl, 23-14.'5)

The present invention relates, in general, to the ,adsorption ofpentavalent vanadium on an anionic exchange material and, moreparticularly, to the use of a catalytic agent-to promotetheadsorpt-ionof .pentavalent vanadium anions on;an: anionicexchange-resinas, for example in a purification or separation process.

As has been disclosed in the copending applications of .Richard H.Bailes and Ray S. Long Serial Nos. 165,532 and 159,744, filed June 1,1950, and May 3, 1950, re- ;spectively, pentavalent vanadium produced inacidic phosphatictsolutions having a complex composition may betadsorbedby anionioexchange resins. Application ,Senial No. 159,744 issued asPatent No. 2,756,123 on July 24, 1956. Application Serial No. 165,532issued ;as;Patent .No. 2,830,874 on April 15, 1958. Subsequentl i theadsorbed anionic pentavalent vanadium complex is eluted by variouslymodified processes to ration and purification of the vanadium and/orother material with which it was associated in -;the original acidicphospha'tic solution.

Various "investigators; including the present; inventors,

have found, -however,- that*the pentavalent vanadium is not adsorbedat-all'or is on1y--very-slowlyadsorbedby anipnic exchange resinsfromacidiophosphatic or -phosphoricacid solutions of more purifiedcompositions. Indeedythe :lack of suecess inobtaining-suchanionic-adsorption of vanadium from such purifiedsolutions appears to have stymied prpgress in the utilization of anionicexchange -recovery and 7 purification processes prior-to'-the-successful accomplishments disclosedin the aforesaidapplications of *Bailes and Long.

Nowthe present inventors have discovered that the addition of catalyticI amounts of materials which supply -eifective concentrations-of-fluoride ion- (F'") to such phosphatic -solutions promotes orgreatly accelerates the adsorption -of pentaval ent vanadium-therefrom"by an anionic exchange resin. Accordingly, vanadium;solutions which hitherto-were not amenable to'treatment by anionicexchange p ocesses sneh; as those disclosed in said .copending.applications may now be processed therein following appropriate.treatment with ,the anionic, exchange promoter .of vthe presentinvention.

,It-is thereforea prime object .of the present invention to introducematerials, which supplyeffective concentrationsof fluoride ion,.intopentavalentvanadium solutions, to promote the anionic exchangeadsorption, of .pentavalent I vanadium; therefrom.

- :Anotherobject of'the invention is toemploymaterials .of .the.,classwhich supplyeffective .coneentrationsof .fluoride ions in.phosphatiosolutions to accelerate .or

.otherwise .promote ,.the adsorption of pentavalent svanadiumtherefromand upon. an anionic exchange. resin .contactingsuch.solution.

[A further; object ofitheinvention is toprovidea process .fonpuri fyingand; recovering-vanadium including the pro- ;rnotionpf anionicadsorption of 'pentavalentyanadium on an; anionic,'exchange;1'e$inbyyrneans of a.;source,-of the solution.

I Arstillfurther objectrof ,theinvention qis .to.,add..-a solubl fi orii ematerial phqspha i v nadinmnsqlutio s t pr rap an n rasedppentavalent:anionic nadium a sorption t he efrcmeby anionicmexehansresins.

- Other: objects and:advantageoussfieaturesgoflthe. present inventionwill become apparent: from consideratio ;of the following description:taken irriconjunction-rwith the accompanying drawing, ofiwhich: 1

, Figure 1711's aflowsheet illustratingqth {Process.of the invention;

'Figure 2 is agraphical.representationyof the-resnltspbtained in-equilibrium experiments indicating the :low vanadiumadsorptions,obtained ;;in; phosphatic olutions of.Simple-zcomposition.ascompared with that orrnally obtained fromalt-impureE industrial, phosphgriqncidnand s sa g p i p s n at nnvnfn hehi hl b efi ial res lts. taine wi fil .:.anienie--.ed o ptinn:ze c a gcin ma elem va a ium whe lusins t prom t n-o t heinven n In general,asiIIustratedJnI- ig; luQf the drawing; the anion exehan erpr ce e w hict en esent nv ion m y b employ d inc ude the treatement of" oluitions,'1 particularly, phosphafi tsnlu nns, deonta nins :pen avak na i m. Fo m,;;s ch. :;p q ess may includ :th Produc ion of -,an',-aQ S1JQTphosphatic so ution cont ni g. a .-'pent valenn a ion c; orm: atwanadium-an snbseque nadserption. f the nionic wana i mw the e-:firamnponananioni exchang resin nFollQwinaadsor-ption, the resinadsorbate may thenzba ;t.lteated-.-by;.-a:mriety of :-;:nro..ed e to..1eif tnpurification 1.3 1 4 sselec ive elution of .th vana iu ilnznaticul ri h presen tinventionrman .bemm'ploye tmefie nadsorption oftp naval nt anionic-1vanadium fr m: recal itrant phosnhatic. solutionswherebyrsucha-r calcitrant solutions are rendered amenable to :treatmentbysthfi processes; disclosed; in the aforesaid applicationsof Bailes andLong. As disclosed in;;the,saidapplications of iBailesgandr Long, crude;phosphoniciaeidisolutions; ;(.or other --.a,cidic phosphatic solutions)- :-.whi,ch dcontain vanadiumiogether :with uranium-.1 fluoride;and: anwariety of othertrnaterials 1 are wtteated; withs powerful'ioxidizing agents whereby: the :vanadium yisv oxidized @to:thepentavalent :state. ;;Such-,oxidatiommay be;efiectedrbyvmeans of 1 vrious agents including ielectrolytic.oxidation; aper-;mangana;te,-;chlorate, hydrogen-peroxide, land-manganese :dioxide.Following, 1 oxidation :the solution 1 is pa ssed through: an (BHIOHlQQXChaHgG- .resinn;column= preferably;of :the: strongly basicztypeof. anionic exchange resinawhere- :upon; the: pentavalent.vanadiumcomplex.-;anions, (uran-yl complex anions,-. and; certain.otheranionic-materials; are adsorbedtherefromnby the resin. :Cationicnaterialslare not :Iadsorhed:-:and, therefore, .-;r.emain.1inzthenetfiuent. Subsequent to adsorption, :the. vanadium is :eluted-ifromthe column ithIubefOIGOI- after .othervmaterials'have been:.=washed .1or eluted; therefrom by.; a procedure 1 includ- ;ing reduction of the;vanadiumwtowthe .-tetravalent.-state and elut-ion:as:.a-.cation. "Theefiluent acidicphosphate soluti-onmay. then be I returned to. a .plant"for phosphate recovery on otherlappropriate treatment.

' .Sulfur dioxide .gas orferrous sulfate :solution" may :be used forthepurpose of selectively: reducing the vanadium to the :tetravalent.state in situ. and; in the presence of uranium and/or ,for.reduc-inglthe vanadium prior to. elution thereof. Simultaneous.selective reduction and 'elution of the vanadium may-,be eflected .with:ant-aqu ous. solution ofi; sulfur dioxide,= .sulfun dioxide .-in dilute.sulfuricacid, or ierrous sulfate.

'In the event that sulfur dioxide;gasiissemployed.-as.;the redu in -.=asn -1 seleetiv ly reducet ead orhed ivanaiu es t .water 0 w taqneonasnlutinnno ssnltw dioxide may be used to elute the tetravalent vanadiumas 'Patent No. 2,770,522, granted November 13,

is employed in a column for this removes phosphate to be obtained in asolution having reduced phosphate contamination. Such vanadium may befurther purified and finally recovered as by the process disclosed inthe copending application of Richard H. 'B-ailes and Robert R.Grinstead, Serial No. 291,946, filed June 6, 1952, now 1956. Uraniumadsorbed on the resin as a uranyl phosphate complex anion may beselectively removed prior to elution of the vanadium by employing adilute hydrochloric acid or chloride salt solution having an eflectiveconcentration less than about 3 -N. The vanadium is then eluted afterreduction orby simultaneous reduction and elution as noted above.Following elution of the vanadium and/ or phosphate the adsorbed uraniumis eluted with a variety of agents including acid solutions, dilutechloride solutions, solutions of hydrochloride salts of various amines,and treatment with concentrated chloride salt solutions followed byelution with water. Such uranium may then be recovered by anyappropriate method.

Accordingly, it may be seen, the operation of such a process whereinboth pentavalent vanadium and uranium are adsorbed on an anionicexchange resin may result in the purification, separation and recoveryof vanadium with or without the recovery of uranium. The presentinvention extends the utility of such a process to those solutions fromwhich, heretofore, pentavalent vanadium could not be adsorbed or couldbe only poorly adsorbed, as will now be disclosed.

In the event that the phosphatic solution is recalcitrant with respectto the adsorption of pentav-alent anionic vanadium therefrom, i. e., inthe event that the solution is deficient in the required anionicadsorption characteristic stemming from an insufliciency orunavailability of fluoride content, it is treated, in accordance withthe present invention, with a fluoridic anionic exchange promoter at anyconvenient time prior to a subsequent anionic adsorption. It isconsidered that any fluoridic material which is capable of supplying aneffective concentration of fluoride ion in the solution is suitable. Forexample, soluble fluoride salts, such as alkali metal fluorides,silicofluorides, hydrofluoric acid, and normally insoluble fluoridessuch as calcium fluoride which can react with or dissolve in an acidicphosphatic solution to yield fluoride ions therein, may be so employed.While such material may be added to the solution at any time prior tothe adsorption step, the material may also be applied to the resin priorto contact with the solution. In any event only a small amount of thepromoter is required as the effect appears to be a catalysis promoted byfluoride.

Following treatment with the adsorption promoter of the invention, thesolution may now be contacted with an anionic exchange material toadsorb the pentavalent vanadium therefrom. Preferably, a highly basicanionic exchange resin, e. -g., a quaternary ammonium base type purpose.Dowex 1 and Dowex 2, strongly basic anionic exchange resins, employed inthe various operations of the following description and illustrativeexamples, are stated by the manufacturer to be equivalent in functionand substantially the same. These materials are manufactured byprocedures which are substantially the same as those described inExamples 2 and 4 of -U. S. Patent No. 2,614,099, filed December 29, 1948, and issued October 14, 1952. Following adsorption, the column maythen be treated in any appropriate process including the variousprocesses disclosed above to separate, purify, and recover the vanadiumand uranium, as desired.

Further details of the manner in which the anionic exchange adsorptionpromoter of the invention is employed to obtain the beneficial results,as well as theoretical aspects of the process, will become apparent byconsideration of the following examples:

EXAMPLE I The necessity for the fluoride ion adsorption promoter isclearly demonstrated by the adsorption results obtained with syntheticsolutions and crude industrial phosphoric acid solution when contactedwith an-ionic exchange resins having various replaceable anions thereon.Such synthetic solutions were prepared from C. P. phosphoric acid andpure chemical compounds as indicated in the following:

For comparison a crude industrial phosphoric acid having the followingcomposition and identified as 6 g. V/liter) (137.9

I is included:

P 0 "percent..- 20.6 S "do-.." 0.66 Fe -do 0.28 A1 0 do 0.75 OaO d 0.29MgO d-o 0.31 Si do 0.09 F- do 1.17 V 0 do 0.26 NaK do 0.05 Sp. G 1.21

Portions of the above solutions were shaken with quantities of a highlybasic anionic exchange resin (Dowex 2 having either chloride or sulfateexchangeable anions) until equilibrium conditions were approached. Thesupernatant solutions were then analyzed for uranium and vanadium andthe amount adsorbed by the resin was calculated as the differencebetween the original and final analyses of the solutions. These resultsare graphically illustrated in Fig. 2.

As may be seen from the graphs of vanadium adsorption from the syntheticsolutions is very low relative to the adsorption from the crudeindustrial phosphoric acid. Also, it may be seen, that neither oxidationnor reduction nor the presence of uranium, chloride, sulfate ormanganese affects the adsorption from such solutions. Uranium adsorption(anionic uranyl phosphate) was normal from solution 2. Therefore, it maybe seen that some factor capable of promoting adsorption and which ispresent in the crude 0 acid is clearly lacking 1n the syntheticsolutions.

EXAMPLE II Upon further consideration and investigation, it wasdiscovered that the addition of fluoridic materials to a syntheticphosphoric acid solution containing pentavalent vanadium obviated theanionic adsorption difficulties. The remarkable efficacy of theadsorption promoter is evident from theresults of the followingexperiments: First there was prepared a series of solutions with thecompositions indicated in the following table by dissolving identicalamounts of V 0 and variable amounts of fiuoridic materials in 30% C. P.phosphoric acid. These solutions were then mixed with portions of highlybasic anionic exchange resin and samples were taken over an extendedperiod of time as indicated in said table and as the vanadiumdistribution between the resin and solution phases approachedequilibrium. The results of the resin adsorption, as well as acomparable adsorption of vanadium from an oxidized industrial said Fig.2, the

may be considered to be invention and it tions as fall within the scopeof the appended claims.

Table VANADIUM EXCHANGE EQUILIBRIUM IN SYNTHETIC SOLUTIONS Gram Mg.Curve Resin Aqid V/l. V/ml. solution resin 1. a3 2 i 1. 32: 2 A Dowex;1, IOU-mesh 6% cross 1inka'ge'(shakeu 21 hrs.)- 30% H,1 o1+v {jg i 61.12 11-6 0. 90 1.1 95 38.7 0:75- 35.2' 13-...-- Dower 2, -100,-meshregular -uross'li n.kage (shaken .16 hrs.) H3PO +V+2.25 gramEF /L .-.l2;.g 01 40' 2118: 0.88. 39. 0 0",--- Dowex- 2; 1 OO-Inesh'regu1ar:crosslinkage (shaken 19 hrs)-.. 30% H1P0l+v+1 gram HF/l g; g; 3:2 0. 41 2.07

0.98 30.8 0. 78 28.4 n Dowex 1, 1 0 m 6% cross linkage (shaken 18 hrs.)30% HaP0l+V+0A gmm tar 1-.-

0.27. 2.00 0. 95* 30.8 0.17 27.4 E Dowex 1, IOU-mesh regular crosslinkage (shaken 19 hrs.).-. 30% HaPO4+V=HLO4 gram'HF/L'.. 8523i &2

0.50 5.21'. 0.36 g 2.23 t 0180 3751 0160 31.2 Dowex 1,100-rnesh regular'cross linkagelshaken 17 hrs)... 30% HtPo1+v+15 gr m/1. merrily-.. 3g;5;; 0.27 1.3 0.26 2. a 1.22 4.0 G IOU-mesh glass (shaken 22 hrs.)Oxidized crude industrial phosphoric acid- As may be seen from curves Aand G of Fig. 3, the anionic resin adsorption of pentavalent vanadiumfrom a synthetic solution which does not contain a fluoridic material isof about the same very low order of magnitude as adsorption by glass, i.e., the adsorption is very slow. However, the anionic exchangeadsorption, by the resin, in the presence of soluble fluoridic materials(F- ions) may be seen to be rapid and relatively complete as indicatedby the asymptotic shape of curves B through F.

The mechanism for the promotion of adsorption by the fluoridic materialsis not fully understood. However, the position of the lower portion ofcurve E, where only 0.04 g./l. of HF was employed, indicates a slow rateof adsorption which may be even slower with lower proportions offluoride present. This phenomena indicates that equilibrium was probablynot reached in the time allowed with the very low concentration offluoride limiting the rate. As the amount of vanadium adsorbed from thissolution B was at least ten equivalents for each equivalent of fluoridepresent, it is obvious that the particular form in which the vanadium isfinally adsorbed is not a fluoride complex. Hence, the foregoingsuggests that the fluoride may temporarily complex the dissolvedpentavalent vanadium to accomplish the adsorption whereupon the fluorideis released to temporarily complex more vanadium and repeat the cycle.

With such a catalytic mechanism the equilibrium amount of vanadiumadsorbed will not be a function of the fluoride concentration but therate of adsorption of the vanadium will be a function of fluorideconcentration as may be noted from the foregoing. Also, as the fluoridedoes not appear to be consumed to any considerable extent in theprocess, it may be seen that the fluoride acts as a truly catalyticpromoter.

While there has been described in the foregoing what preferredembodiments of various modifications may be made departing from theteachings of the is intended to cover all such modificathe invention,therein without What is claimed is:

1. In a process for recovering vanadium'from an anionic exchangerecalcitrant acidic phosphatic solution, the steps comprising oxidizingthe vanadium in the solution to the pentavalent state, adding afluoridic anionic exchange promoter to the solution, contacting saidsolution with an anionic exchange resin whereby the adsorption of thepentavalent vanadium is eflectuated thereon by said promoter, andeluting said vanadium from said resin.

2. In a process for recovering vanadium from an anionic exchangerecalcitrant acidic phosphate solution, the steps comprising oxidizingthe vanadium in the solution to the pentavalent state, adding to saidsolution a fluoridic material selected from the group consisting ofsoluble fluoride salts, hydrofluoric acid, silicofluorides and normallyinsoluble fluoride salts capable of reacting with and dissolving in saidsolution, contacting said solution with an anionic exchange resinwhereby the adsorption of the pentavalent vanadium is effectuatedthereon by said fluoridic material, and eluting said vanadium from saidresin.

3. In an anionic exchange process for recovering vanadium from amaterial, the steps comprising producing an acidic phosphatic solutionof said material containing the vanadium in the pentavalent oxidationstate, said solution being recalcitrant and deficient in the requiredpentavalent anionic vanadium exchange adsorption characteristic,treating an anionic exchange resin column with a fluoridic adsorptionpromoter, contacting said solution with said treated resin columnwhereby the adsorption of pentavalent vanadium is eirectuated thereon bysaid fluoridic promoter, and eluting the vanadium from the resin.

4. In an anionic exchange process for recovering vanadium and uraniumvalues from an oxidized acidic phosphatic solution which is recalcitrantand deficient in the required pentavalent anionic vanadium exchangecharacteristic, the steps comprising adding a fluoridic anionic exchangepromoter to said solution, contacting said solution with an anionicexchange resin column, whereby hexavalent uranium and pentavalentvanadium complex anions are adsorbed thereon, selectively eluting theuranium from the resin with an elutriant selected from the groupconsisting of dilute hydrochloric acid and chloride salt solution ofless than 3 N concentration, and then simultaneously reducing andeluting vanadium therefrom with an elutriant selected from the groupconsisting of aqueous solutions of S0 H SO +SO and FeSO,;.

5. In an anionic exchan'ge'process for recovering vanadium and uraniumvalues fro m an oxidized acidic phosselected from the group consistingof S0 H SO +SO i phatic solution which is recalcitrant and deficient inthe required pentavalent anionic vanadium exchange characteristic, thesteps comprising adding a fluoridic anionic exchange promoter to said.solution, contacting said solution with an anionic exchange resincolumn, whereby hexavalent uranium and pentavalent vanadium complexanions are adsorbed thereon, selectively eluting the uranium from theresin with an elutriant selected from the group consisting of dilutehydrochloric acid and chloride salt solution of less than 3 Nconcentration, reducing the anions are adsorbed thereon, simultaneouslyselectively reducing and eluting vanadium as a tetravalent cation fromthe resin with; an elutriant solution of a material and FeSO and elutinguranium from the resin.

7. In a process wherein'pentavalent vanadium anionic complexes areabsorbed on a strongly basic anionic exchange resin from an acidicphosphatic solution, the step comprising adding a soluble fluoridicmaterial to a recalcitrant acidic phosphatic solution of pentavalentva-- nadium to provide said acidic phosphatic solution wherefromadsorption of said pentavalent vanadium anionic complexes is promotedand effected.

8. The process as otherwise defined in claim 7' but wherein said solublefluoridic material comprises a material selected from the groupconsisting of soluble fluoride salts, silicofluoride's, and insolublefluoride salts dis solvable in said phosphatic solution to provide anappre ciable concentration of fluoride ions thereln.

References Cited in the file of this patent UNITED STATES PATENTS2,756,123 Bailes et al. July 24, 1956 OTHER REFERENCES Mellor: ModernInorganic Chemistry, new edition,

revised and edited 1951, page 492. mans, Green & Co., London.

Publ. by Long-

1. IN A PROCESS FOR RECOVERING VANADIUM FROM AN ANIONIC EXCHANGERECALCITRANT ACIDIC PHOSPHATIC SOLUTION, THE STEPS COMPRISING OXIDIZINGTHE VANADIUM IN THE SOLUTION TO THE PENTAVALENT STATE, ADDING AFLUORIDIC ANIONIC EXCHANGE PROMOTER TO THE SOLUTION, CONTACTING SAIDSOLUTION WITH AN ANIONIC EXCHANGE RESIN WHEREBY THE ADSORPTION OF THEPENTAVALENT VANADIUM IS EFFECTUATED THEREON BY SAID PROMOTER, ANDELUTING SAID VANADIUM FROM SAID RESIN.